now the obama camp has released a new tongue-in-cheek ad casting an unlikely star as a criminal master mine. will it be effective? take a look for yourself and decide. >> i'm barack obama and i approve this message. >> bernie madoff, dennis keselowski, criminals, gluttons of greed and the evil genius who towered over them. one man has the guts to speak his name. >> big bird. >> big bird. >> it's me, big bird. >> big, yellow, a menace to our economy. mitt romney knows it's not wall street you have to worry about, it's sesame street. >> i'm going to stop the subsidy to pbs. >> mitt romney taking on our enemies no matter where they nest. >> this comes as the 2012 presidential election is just four weeks away, and now new polls show the race between president obama and republican rival mitt romney is closer than ever. nbc's tracie potts has more from washington. good morning to you. >> reporter: good morning. they're raising a lot of money, too. which is why we'll see more of those ads. romney today in iowa and ohio. speaking of campaign slogans, turns out he may end up repeating a new one